US4314978A - Increased production of wet process phosphoric acid by gelatin addition - Google Patents
Increased production of wet process phosphoric acid by gelatin addition Download PDFInfo
- Publication number
- US4314978A US4314978A US06/229,468 US22946881A US4314978A US 4314978 A US4314978 A US 4314978A US 22946881 A US22946881 A US 22946881A US 4314978 A US4314978 A US 4314978A
- Authority
- US
- United States
- Prior art keywords
- gelatin
- phosphoric acid
- calcium sulphate
- added
- sulphate crystals
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 78
- 108010010803 Gelatin Proteins 0.000 title claims abstract description 49
- 229920000159 gelatin Polymers 0.000 title claims abstract description 49
- 239000008273 gelatin Substances 0.000 title claims abstract description 49
- 235000019322 gelatine Nutrition 0.000 title claims abstract description 49
- 235000011852 gelatine desserts Nutrition 0.000 title claims abstract description 49
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 60
- 238000001914 filtration Methods 0.000 claims abstract description 30
- 239000013078 crystal Substances 0.000 claims abstract description 29
- 235000011132 calcium sulphate Nutrition 0.000 claims abstract description 28
- 239000001175 calcium sulphate Substances 0.000 claims abstract description 24
- 238000006243 chemical reaction Methods 0.000 claims abstract description 16
- 230000002411 adverse Effects 0.000 claims abstract description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 12
- 229910019142 PO4 Inorganic materials 0.000 claims description 11
- 239000010452 phosphate Substances 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 150000004683 dihydrates Chemical group 0.000 claims description 6
- 150000007522 mineralic acids Chemical class 0.000 claims description 6
- 238000010790 dilution Methods 0.000 claims description 5
- 239000012895 dilution Substances 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 239000012141 concentrate Substances 0.000 claims description 3
- 239000002253 acid Substances 0.000 abstract description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 12
- 239000002002 slurry Substances 0.000 description 8
- 239000002367 phosphate rock Substances 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 230000029087 digestion Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229910052602 gypsum Inorganic materials 0.000 description 4
- 239000010440 gypsum Substances 0.000 description 4
- 239000001117 sulphuric acid Substances 0.000 description 4
- 235000011149 sulphuric acid Nutrition 0.000 description 4
- 238000000926 separation method Methods 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 229910052925 anhydrite Inorganic materials 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- QNRATNLHPGXHMA-XZHTYLCXSA-N (r)-(6-ethoxyquinolin-4-yl)-[(2s,4s,5r)-5-ethyl-1-azabicyclo[2.2.2]octan-2-yl]methanol;hydrochloride Chemical compound Cl.C([C@H]([C@H](C1)CC)C2)CN1[C@@H]2[C@H](O)C1=CC=NC2=CC=C(OCC)C=C21 QNRATNLHPGXHMA-XZHTYLCXSA-N 0.000 description 1
- 229910003556 H2 SO4 Inorganic materials 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 210000000988 bone and bone Anatomy 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- ZOMBKNNSYQHRCA-UHFFFAOYSA-J calcium sulfate hemihydrate Chemical compound O.[Ca+2].[Ca+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O ZOMBKNNSYQHRCA-UHFFFAOYSA-J 0.000 description 1
- PURUTDMXEWDKMF-UHFFFAOYSA-L calcium;phosphoric acid;sulfate Chemical compound [Ca+2].OP(O)(O)=O.[O-]S([O-])(=O)=O PURUTDMXEWDKMF-UHFFFAOYSA-L 0.000 description 1
- 238000003889 chemical engineering Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 210000002808 connective tissue Anatomy 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000012065 filter cake Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical class [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 1
- 229940085991 phosphate ion Drugs 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000010517 secondary reaction Methods 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 210000003491 skin Anatomy 0.000 description 1
- 150000003460 sulfonic acids Chemical class 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 238000003911 water pollution Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/22—Preparation by reacting phosphate-containing material with an acid, e.g. wet process
- C01B25/222—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with sulfuric acid, a mixture of acids mainly consisting of sulfuric acid or a mixture of compounds forming it in situ, e.g. a mixture of sulfur dioxide, water and oxygen
- C01B25/223—Preparation by reacting phosphate-containing material with an acid, e.g. wet process with sulfuric acid, a mixture of acids mainly consisting of sulfuric acid or a mixture of compounds forming it in situ, e.g. a mixture of sulfur dioxide, water and oxygen only one form of calcium sulfate being formed
Definitions
- This invention relates to the increased production of phosphoric acid, and, more particularly, to the increased production of phosphoric acid by the addition of gelatin to the reaction system.
- Phosphoric acid is produced in the traditional wet process by the action of an inorganic acid on phosphate rock, producing phosphoric acid and the calcium salt of the acid used.
- Sulfuric acid is the preferred inorganic acid in that it produces an insoluble calcium sulfate which may be filtered.
- the calcium sulfate may be precipitated as a dihydrate (CaSO 4 .2H 2 O) which is also known as gypsum, or as a hemihydrate (CaSO 4 .1/2 H 2 O), or as an anhydrite (CaSO 4 ).
- the dihydrate process involves the digestion of phosphate rock with strong sulfuric acid and weak recycled phosphoric acid for a given period of time, the time required to fully develop filterable and washable gypsum crystals.
- a single, or multiple, reaction tank may be utilized.
- the slurry is continuously drawn off, cooled, and filtered.
- the gypsum is finally washed with wash liquor containing approximately 2-5% P 2 O 5 , and the washed gypsum is disposed of. This process produces approximately a 30% P 2 O 5 acid, which can then be concentrated to higher P 2 O 5 levels.
- the separation of calcium sulphate from phosphoric acid is an important step. This separation is generally accomplished by filtration using any number of well known devices.
- the large quantities of phosphoric acid produced in commercial plants requires filters of large area and complexity in order to insure good separation and recovery of the phosphoric acid. These filters are costly and difficult to maintain in good operating condition.
- the concentration of phosphoric acid produced is limited to about 30% P 2 O 5 because higher concentrations cause lower filtration rates. These low rates are due to changes in the calcium sulfate crystals which are produced as by-product in wet process phosphoric acid.
- Phosphoric acid of greater than 45% P 2 O 5 is more desireable to produce, but the calcium sulphate hemihydrate crystals which are produced in this concentration range are very difficult to filter.
- the size and shape of the calcium sulphate crystals are extremely important factors in proper filtration and washing.
- the three most important factors effecting crystal growth are:
- An object of this invention is the improvement of the filtration rate of the phosphoric acid-calcium sulphate slurry formed in the production of wet process phosphoric acid. This improvement will allow a smaller filtration area to be used in phosphoric acid plants and will also permit increased production in plants where current filtration area is limited. Since the filtration rate generally decreases as the concentration of the phosphoric acid increases, this invention will allow higher strength phosphoric acid to be produced without an increase in filtration area necessary. This invention also has application to the production of strong phosphoric acid such as that made in a hemihydrate process.
- the present invention improves the filtration rate of the slurry produced in the phosphoric acid wet process by from about 5% to about 30%, and this increased filtration rate is accomplished by adding relatively small amounts of gelatin to the reaction system.
- the addition of gelatin to the reaction system does not affect the color or viscosity of the phosphoric acid.
- a preferred embodiment of the present invention comprises adding at least about 0.05 lb. to about 5.0 lb. of gelatin per short ton of P 2 O 5 in phosphate containing material.
- a second preferred embodiment of the present invention comprises adding a relatively small amount of gelatin to increase the filtration rate of the calcium sulphate crystals from about at least 5% to about 30%.
- a third preferred embodiment of the present invention is utilizing a gelatin selected from the group comprising all commercial grades of gelatin, including any material derived from the bones, connective tissue, or skin of animals.
- a further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the dihydrate form.
- a second further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the hemihydrate form.
- a third further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the anhydrite form.
- gelatin can, under laboratory conditions, slow the growth rate of calcium sulphate crystals.
- the present invention improves the filtration rate of the slurry (i.e. calcium sulphate and phosphoric acid) produced in the phosphoric acid wet process.
- the addition of relatively small amounts of gelatin (i.e. at least about 0.1 lb. of gelatin per short ton of P 2 O 5 ) to the phosphoric acid reaction system will increase the filtration rate of the calcium sulphate crystals from about at least 5% over that of a system which does not contain gelatin.
- An enhanced filtration rate increase as great as 30% has been obtained using about 0.2 lbs. of gelatin per short ton of P 2 O 5 in phosphate containing material in a dihydrate process.
- the gelatin can be any one of the following readily available commercial products: pharmaceutical grade, photographic grade, edible grade, or technical grade, and, preferably, it should be technical grade.
- the gelatin can be added with any of the feedstocks, or it can be added directly to the reaction system.
- the gelatin should be added to the sulphuric acid dilution water or directly to the digestor where the phosphate concentrate is added.
- the gelatin can be added to the system as an aqueous solution, containing about 60 grams of gelatin per liter of solution, with the temperature of the solution being maintained at about 100° F.
- the aqueous gelatin solution can be prepared on a continuous basis in a mixing tank, with the gelatin and water being fed continuously to a constantly stirred, heated tank.
- gelatin in addition to being relatively cheap (i.e. $1.50 to $2.00 per pound), has no adverse affect on the quality of the phosphoric acid produced.
- the use of gelatin in the wet process reaction system does not increase the color or viscosity of the phosphoric acid.
- a phosphoric acid pilot plant producing about 0.4 lb. of P 2 O 5 per hour was operated on a semi-continuous basis.
- Three digestion cells of 2.7 liter each were used in a simulation of the Prayon design. Phosphate rock and recycle acid were added to the first digestion cell. Sulfuric acid was diluted to about 50% H 2 SO 4 before being added to the second cell. Slurry was recycled from the third cell to the first cell. U.S.P. grade gelatin in the amount of about 0.1 lb. per ton of P 2 O 5 was added to the sulphuric acid dilution water. Filtration tests were performed using slurry produced by the pilot plant. While producing product acid containing about 26% P 2 O 5 acid, an increase in filtration rate of 10.2% was obtained. While producing acid containing 30% P 2 O 5 , an increase of 18.8% was obtained.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Paper (AREA)
Abstract
An improved method for the production of wet process phosphoric acid wherein the addition of relatively small amounts of gelatin to the reaction system substantially increases the filtration rate of the calcium sulphate crystals without adversely affecting the quality of the acid.
Description
1. Field of the Invention
This invention relates to the increased production of phosphoric acid, and, more particularly, to the increased production of phosphoric acid by the addition of gelatin to the reaction system.
2. Description of the Prior Art
Phosphoric acid is produced in the traditional wet process by the action of an inorganic acid on phosphate rock, producing phosphoric acid and the calcium salt of the acid used. Sulfuric acid is the preferred inorganic acid in that it produces an insoluble calcium sulfate which may be filtered. The calcium sulfate may be precipitated as a dihydrate (CaSO4.2H2 O) which is also known as gypsum, or as a hemihydrate (CaSO4.1/2 H2 O), or as an anhydrite (CaSO4).
The overall reaction for the dihydrate process is usually indicated as follows:
Ca.sub.5 (PO.sub.4).sub.3 F+5H.sub.2 SO.sub.4 +10H.sub.2 O→3H.sub.3 PO.sub.4 +5CaSO.sub.4.2H.sub.2 O+HF
There are also many secondary reactions which occur depending on the other minerals of the apatite series present in the phosphate rock. The dihydrate process involves the digestion of phosphate rock with strong sulfuric acid and weak recycled phosphoric acid for a given period of time, the time required to fully develop filterable and washable gypsum crystals. A single, or multiple, reaction tank may be utilized. The slurry is continuously drawn off, cooled, and filtered. The gypsum is finally washed with wash liquor containing approximately 2-5% P2 O5, and the washed gypsum is disposed of. This process produces approximately a 30% P2 O5 acid, which can then be concentrated to higher P2 O5 levels.
The principal objectives of any commercial phosphoric acid process should be:
1. To extract the maximum amount of P2 O5 from the phosphate rock.
2. To precipitate a rapidly filtering and easily washable calcium sulfate.
3. To produce a phosphoric acid having as high a P2 O5 content as possible.
4. Continuous production over long periods at design capacities.
5. Minimum operating, labor, and maintenance costs.
6. Safe, clean plant operation, with absence of air and water pollution.
In the production of phosphoric acid by the wet process, the separation of calcium sulphate from phosphoric acid is an important step. This separation is generally accomplished by filtration using any number of well known devices. The large quantities of phosphoric acid produced in commercial plants requires filters of large area and complexity in order to insure good separation and recovery of the phosphoric acid. These filters are costly and difficult to maintain in good operating condition. In general, the concentration of phosphoric acid produced is limited to about 30% P2 O5 because higher concentrations cause lower filtration rates. These low rates are due to changes in the calcium sulfate crystals which are produced as by-product in wet process phosphoric acid. Phosphoric acid of greater than 45% P2 O5 is more desireable to produce, but the calcium sulphate hemihydrate crystals which are produced in this concentration range are very difficult to filter.
The size and shape of the calcium sulphate crystals are extremely important factors in proper filtration and washing. The three most important factors effecting crystal growth are:
1. sulfate ion content;
2. phosphate ion content; and,
3. type and amount of impurities present.
Operating conditions and reactor design also influence crystal formation. The most desireable crystal forms would be rhombic or clusterlike, and the least desired would be needlelike or platelike crystals.
The effect of impurities on the filterability of calcium sulphate crystals has been discussed in Industrial and Engineering Chemistry Process Design and Development, 388, October 1966 (Gilbert, R.), and a summary of phosphoric acid filtration is presented in Chemical Engineering, 137, Aug. 15, 1966 (James, G. R.). An article by E. R. McCartney and A. E. Alexander entitled "The Effect of Additives upon the Process of Crystallization", Journal of Colloid Science 13, 383-396 (1958), describes the effects of gelatin on calcium sulphate crystal growth.
An object of this invention is the improvement of the filtration rate of the phosphoric acid-calcium sulphate slurry formed in the production of wet process phosphoric acid. This improvement will allow a smaller filtration area to be used in phosphoric acid plants and will also permit increased production in plants where current filtration area is limited. Since the filtration rate generally decreases as the concentration of the phosphoric acid increases, this invention will allow higher strength phosphoric acid to be produced without an increase in filtration area necessary. This invention also has application to the production of strong phosphoric acid such as that made in a hemihydrate process. The present invention improves the filtration rate of the slurry produced in the phosphoric acid wet process by from about 5% to about 30%, and this increased filtration rate is accomplished by adding relatively small amounts of gelatin to the reaction system. The addition of gelatin to the reaction system does not affect the color or viscosity of the phosphoric acid.
In a method for producing wet process phosphoric acid in a reaction system wherein at least one inorganic acid is reacted with a phosphate containing material for a period of time sufficient to develop filterable washable calcium sulphate crystals, the improvement comprising:
Adding a relatively small amount of gelatin to said reaction system to substantially increase the filtration rate of said calcium sulphate crystals without adversely affecting the quality of said wet process phosphoric acid.
A preferred embodiment of the present invention comprises adding at least about 0.05 lb. to about 5.0 lb. of gelatin per short ton of P2 O5 in phosphate containing material.
A second preferred embodiment of the present invention comprises adding a relatively small amount of gelatin to increase the filtration rate of the calcium sulphate crystals from about at least 5% to about 30%.
A third preferred embodiment of the present invention is utilizing a gelatin selected from the group comprising all commercial grades of gelatin, including any material derived from the bones, connective tissue, or skin of animals.
A further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the dihydrate form.
A second further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the hemihydrate form.
A third further preferred embodiment of each of the foregoing preferred embodiments is the filtration of calcium sulphate crystals that are substantially in the anhydrite form.
The size and shape of the calcium sulphate crystals formed during the digestion phase of the wet process greatly effect the filtration rate of the phosphoric acid slurry. There are certain compounds well known in the wet process phosphoric acid art for affecting the calcium sulphate crystal habit, the most commonly used being sulfonic acid salts.
The previously cited article from the Journal of Colloid Science teaches that gelatin can, under laboratory conditions, slow the growth rate of calcium sulphate crystals. I have now discovered, quite surprisingly, that the addition of a relatively small amount of gelatin to a wet process phosphoric acid reaction system will significantly increase the filtration rate of calcium sulphate crystals without adversely affecting the quality of the phosphoric acid.
The present invention improves the filtration rate of the slurry (i.e. calcium sulphate and phosphoric acid) produced in the phosphoric acid wet process. The addition of relatively small amounts of gelatin (i.e. at least about 0.1 lb. of gelatin per short ton of P2 O5) to the phosphoric acid reaction system will increase the filtration rate of the calcium sulphate crystals from about at least 5% over that of a system which does not contain gelatin. An enhanced filtration rate increase as great as 30% has been obtained using about 0.2 lbs. of gelatin per short ton of P2 O5 in phosphate containing material in a dihydrate process.
The gelatin can be any one of the following readily available commercial products: pharmaceutical grade, photographic grade, edible grade, or technical grade, and, preferably, it should be technical grade.
The gelatin can be added with any of the feedstocks, or it can be added directly to the reaction system. Preferably, the gelatin should be added to the sulphuric acid dilution water or directly to the digestor where the phosphate concentrate is added. The gelatin can be added to the system as an aqueous solution, containing about 60 grams of gelatin per liter of solution, with the temperature of the solution being maintained at about 100° F. The aqueous gelatin solution can be prepared on a continuous basis in a mixing tank, with the gelatin and water being fed continuously to a constantly stirred, heated tank.
It is important to note that the gelatin, in addition to being relatively cheap (i.e. $1.50 to $2.00 per pound), has no adverse affect on the quality of the phosphoric acid produced. The use of gelatin in the wet process reaction system does not increase the color or viscosity of the phosphoric acid.
The following examples will illustrate various ways in which the principle of the invention may be applied, but are not to be construed as limiting the invention.
A phosphoric acid pilot plant producing about 0.4 lb. of P2 O5 per hour was operated on a semi-continuous basis. Three digestion cells of 2.7 liter each were used in a simulation of the Prayon design. Phosphate rock and recycle acid were added to the first digestion cell. Sulfuric acid was diluted to about 50% H2 SO4 before being added to the second cell. Slurry was recycled from the third cell to the first cell. U.S.P. grade gelatin in the amount of about 0.1 lb. per ton of P2 O5 was added to the sulphuric acid dilution water. Filtration tests were performed using slurry produced by the pilot plant. While producing product acid containing about 26% P2 O5 acid, an increase in filtration rate of 10.2% was obtained. While producing acid containing 30% P2 O5, an increase of 18.8% was obtained.
During operation of a Prayon phosphoric acid plant designed to produce 525 TPD of P2 O5, edible grade gelatin was continuously added for a six-day period in the amount of about 0.2 lb. per ton of P2 O5. The gelatin was batch-mixed in a tank with water as a 120 g/l lyophilic solution at 125° F. The solution was added to the sulphuric acid dilution water prior to mixing with the sulphuric acid. The filtration rate of the slurry was increased by an average of 10% during gelatin addition as compared to operation with no gelatin addition. The filtration rate increase was as high as 30% when operating at a relatively low sulphate concentration of 1.9% sulfuric acid. The gelatin addition did not affect the phosphate losses in the filter cake.
Claims (12)
1. In a method for producing wet process phosphoric acid in a reaction system wherein at least one inorganic acid is reacted with a phosphate containing material for a period of time sufficient to develop filterable and washable calcium sulphate crystals, the improvement comprising:
adding a relatively small amount of gelatin to said reaction system to substantially increase the filtration rate of said calcium sulphate crystals without adversely affecting the quality of said wet process phosphoric acid.
2. In a method according to claim 1, wherein said relatively small amount of gelatin is at least about 0.05 lb. of gelatin per short ton of P2 O5 in phosphate containing material.
3. In a method according to claim 1, wherein the filtration rate of said calcium sulphate crystals is increased from about five percent to about thirty percent.
4. In a method according to claim 1, wherein said relatively small amount of gelatin is at least about 0.05 lb. of gelatin per short ton of P2 O5 in phosphate containing material and the filtration rate of said calcium sulphate crystals is increased from about at least about five percent.
5. In a method according to either claims 1 or 4, wherein said calcium sulphate crystals are substantially in the dihydrate form.
6. In a method according to either claims 1 or 4, wherein said calcium sulphate crystals are substantially in the hemihydrate form.
7. In a method according to either claims 1 or 4, wherein said calcium sulphate crystals are substantially in the anhydrite form.
8. In a method according to either claims 1 or 4, wherein said gelatin is selected from the group comprising all commercial grades of gelatin products.
9. In a method according to claim 1, wherein said gelatin is technical grade gelatin.
10. In a method according to claim 1, wherein said gelatin is added to said reaction system as an aqueous solution.
11. In a method according to claim 10, wherein said aqueous gelatin solution is added to the inorganic acid dilution water or to the digestor where the phosphate concentrate is added.
12. In a method according to claim 1, wherein said relatively small amount of gelatin is at least about 0.05 lb. of gelatin per short ton of P2 O5 in phosphate containing material; wherein said gelatin is technical grade gelatin; wherein said gelatin is added to said reaction system as an aqueous solution; and, wherein said aqueous gelatin solution is added to the inorganic acid dilution water or to the digestor where the phosphate concentrate is added.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/229,468 US4314978A (en) | 1981-01-29 | 1981-01-29 | Increased production of wet process phosphoric acid by gelatin addition |
| CA000392336A CA1148328A (en) | 1981-01-29 | 1981-12-15 | Increased production of wet process phosphoric acid by gelatin addition |
| MA19570A MA19366A1 (en) | 1981-01-29 | 1982-01-04 | Improved wet phosphoric acid process by adding gelatin |
| JP57003974A JPS57145014A (en) | 1981-01-29 | 1982-01-13 | Production of wet treating phosphoric acid by adding gelatin |
| EP82300196A EP0057519B1 (en) | 1981-01-29 | 1982-01-14 | A method for increasing the filtration rate of the calcium sulphate crystals in the production of wet process phosphoric acid |
| DE8282300196T DE3260639D1 (en) | 1981-01-29 | 1982-01-14 | A method for increasing the filtration rate of the calcium sulphate crystals in the production of wet process phosphoric acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/229,468 US4314978A (en) | 1981-01-29 | 1981-01-29 | Increased production of wet process phosphoric acid by gelatin addition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US4314978A true US4314978A (en) | 1982-02-09 |
Family
ID=22861375
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US06/229,468 Expired - Fee Related US4314978A (en) | 1981-01-29 | 1981-01-29 | Increased production of wet process phosphoric acid by gelatin addition |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4314978A (en) |
| EP (1) | EP0057519B1 (en) |
| JP (1) | JPS57145014A (en) |
| CA (1) | CA1148328A (en) |
| DE (1) | DE3260639D1 (en) |
| MA (1) | MA19366A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5009873A (en) * | 1990-01-29 | 1991-04-23 | Nalco Chemical Company | Crystal modification in wet process phosphoric acid production |
| US8669396B2 (en) | 2009-05-18 | 2014-03-11 | Monsanto Technology Llc | Recovery of phosphorus values and salt impurities from aqueous waste streams |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB376178A (en) * | 1930-12-23 | 1932-07-07 | Bataafsche Petroleum | Process for purifying phosphatic liquids |
| US2133251A (en) * | 1937-10-06 | 1938-10-11 | Nat Lead Co | Clarification and purification of industrial acid liquors |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4140748A (en) * | 1976-07-07 | 1979-02-20 | Occidental Petroleum Corporation | Hemihydrate type phosphoric acid process with crystal modifier |
| US3562154A (en) * | 1965-05-26 | 1971-02-09 | Johns Manville | High efficiency filter aid |
-
1981
- 1981-01-29 US US06/229,468 patent/US4314978A/en not_active Expired - Fee Related
- 1981-12-15 CA CA000392336A patent/CA1148328A/en not_active Expired
-
1982
- 1982-01-04 MA MA19570A patent/MA19366A1/en unknown
- 1982-01-13 JP JP57003974A patent/JPS57145014A/en active Pending
- 1982-01-14 DE DE8282300196T patent/DE3260639D1/en not_active Expired
- 1982-01-14 EP EP82300196A patent/EP0057519B1/en not_active Expired
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB376178A (en) * | 1930-12-23 | 1932-07-07 | Bataafsche Petroleum | Process for purifying phosphatic liquids |
| US2133251A (en) * | 1937-10-06 | 1938-10-11 | Nat Lead Co | Clarification and purification of industrial acid liquors |
Non-Patent Citations (3)
| Title |
|---|
| Chemical Engineering, 137, Aug. 15, 1966 (James, G. R.). * |
| Industrial and Engineering Chemistry Process Design and Development, 388, Oct. 1966 (Gilbert, R.). * |
| Journal of Colloid Science, 13, 383-396, 1958 (McCartney, E. R. and Alexander, A. E.). * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5009873A (en) * | 1990-01-29 | 1991-04-23 | Nalco Chemical Company | Crystal modification in wet process phosphoric acid production |
| US8669396B2 (en) | 2009-05-18 | 2014-03-11 | Monsanto Technology Llc | Recovery of phosphorus values and salt impurities from aqueous waste streams |
| US9394173B2 (en) | 2009-05-18 | 2016-07-19 | Monsanto Technology Llc | Recovery of phosphorus values and salt impurities from aqueous waste streams |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3260639D1 (en) | 1984-10-11 |
| CA1148328A (en) | 1983-06-21 |
| MA19366A1 (en) | 1982-10-01 |
| EP0057519B1 (en) | 1984-09-05 |
| EP0057519A1 (en) | 1982-08-11 |
| JPS57145014A (en) | 1982-09-07 |
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